1. Field of the Invention
The present invention relates to an optical apparatus (lens apparatus) and a camera system used in television cameras or video cameras or the like, and more particularly, to an optical apparatus and a camera system having a zoom lens system etc. which are used in an ENC camera etc.
2. Description of the Related Art
As image-taking apparatuses using a television camera or a video camera, products which can provide various image-taking methods for storing arbitrarily zoom positions or speeds in memory and also for reproducing them have been sold and used by user. In order to realize such image-taking methods easily and precisely, and to further make them compact, there have been disclosed Japanese Patent Application Laid-Open No. 2001-124979 and EP A2 1096286.
Among these various image-taking methods, typical examples of image-taking methods are as follows.
First, there is an image-taking method in which a zoom lens unit is moved with a predetermined, constant speed corresponse to a predetermined zoom magnification for image-taking. And, in contrast to this method, there is proposed an image-taking method having the following function. That is, an arbitrary zoom position is stored in memory in advance as a preset position and an arbitrary zoom lens drive speed is stored in memory in advance as a preset speed. When a switch is turned on during image-taking, a zoom lens unit is moved to the preset position with the preset speed. In the specification, this preset function is referred to as “position preset zoom control”.
Second, there is an image-taking method in which a zoom lens unit is moved in a predetermined zoom direction with a predetermined speed for image-taking. And, in contrast to this method, there is proposed an image-taking method having the following function. That is, an arbitrary zoom lens drive direction is stored in memory in advance as a preset direction, an arbitrary zoom lens drive speed is stored in memory in advance as a preset speed, and when a switch is turned on during image-taking, the zoom lens unit is moved in the preset direction with the preset speed. In the specification, this preset function is referred to as “speed preset zoom control”.
In the above-mentioned “position preset zoom control” and “speed preset zoom control”, a preset position, a preset speed, and a preset direction must be stored in a storage section. Below, a storing method and an operation method of the preset position, speed, and direction will be explained in reference to FIG. 6.
In FIG. 6, reference numeral 1 denotes a zoom control switch which is controlled by user, reference numeral 2 denotes an instruction signal generating section which generates an instruction signal to instruct a drive direction and a drive speed (which may be replaced by a drive amount and a drive position) proportional to an operation amount of the zoom control switch 1 in order to electrically drive a zoom lens optical system 7 which will be described below.
Reference numeral 3 denotes a zoom speed variable volume which varies the drive speed of the below-described zoom lens optical system 7 in response to the operation amount of the zoom control switch 1, reference numeral 4 denotes an instruction signal calculation section which performs signal level and shift conversion for inputting the instruction signal into a below-mentioned A/D converter 5, and reference numeral 5 denotes the A/D converter which converts an analog signal outputted from the instruction signal calculation section 4 to a digital signal.
Reference numeral 6 denotes a CPU which is responsible for the drive of a preset function, reference character 6a denotes a storage section (memory), installed in the CPU 6, which can store the preset position, the preset speed, etc., and reference numeral 7 denotes a zoom lens optical system which performs zooming of a lens apparatus.
Reference numeral 8 denotes a D/A converter which converts a digital signal from the CPU 6 as the instruction signal outputted for driving the zoom lens optical system 7 to an analog signal, and reference numeral 9 denotes the instruction signal calculation section which performs signal level and shift conversion of the instruction signal outputted from the D/A converter 8.
Reference numeral 10 denotes an instruction signal switching section which switches the drive of the zoom lens optical system 7 from the zoom control switch 1, or from the CPU 6, reference numeral 11 denotes an electric power amplifier which drives a below-mentioned motor 12, reference numeral 12 denotes the motor which drives the zoom lens optical system 7, and reference numeral 13 denotes a speed signal detection section which outputs a speed signal in accordance with a drive speed of the zoom lens optical system 7.
Reference numeral 14 denotes a speed signal calculation section which performs signal level and shift conversion for inputting the speed signal into a below-mentioned A/D converter 15, and reference numeral 15 denotes an A/D converter which converts an analog signal outputted from the speed signal calculation section 14 to a digital signal.
Reference numeral 16 denotes a position signal detection section which outputs a position signal corresponding to a position of the zoom lens optical system 7, and reference numeral 17 denotes a position signal calculation section which performs signal level and shift conversion for inputting a position signal into a below-mentioned A/D converter 18.
Reference numeral 18 denotes an A/D converter which converts an analog signal outputted from the position signal calculation section 17 to a digital signal, and reference numeral 20 denotes a position preset zoom switch which instructs the start or end of the preset drive of position preset zoom.
Reference numeral 22 denotes a speed preset zoom switch which instructs the start or end of the preset drive of speed preset zoom, and reference numeral 24 denotes a memory switch which instructs the memory information regarding the preset position, preset speed and preset direction of the various functions mentioned above. In a lens apparatus or a lens drive unit having the above-mentioned structure, as preparatory work for storing a preset position in memory, it is necessary to motor-driving the zoom lens optical system 7 up to the preset position, or to motor-driving the zoom lens optical system 7 in advance for storing the preset speed in memory.
Here, at first, drive control from the zoom control switch 1 to the zoom lens optical system 7 will be explained. Once the zoom control switch 1 is operated, an instruction signal which instructs the drive direction and drive speed (which may be replaced by a drive amount or drive position) proportional to its drive amount is outputted from the instruction signal generating section 2. This instruction signal is inputted into the electric power amplifier 11 via the zoom speed variable volume 3, which varies drive speed of the zoom lens optical system 7 in response to the drive amount of the zoom control switch 1, and via the A side of the instruction signal switching section 10, and, after amplified to a predetermined level by the electric power amplifier 11, it is inputted into the motor 12. After the above procedure, the motor 12 starts operation and the zoom lens optical system 7 is in operation.
Next, the memory setting procedure of the preset position, preset speed, and preset direction will be explained.
At first, the memory setting procedure of the preset position will be explained. When the preset position is stored in memory, the position required for the zoom lens optical system 7 can be detected by inputting the output from the position signal detection section 16 into the CPU 6 via the position signal calculation section 17 and the A/D converter 18.
In this memory setting procedure, an image-taker moves in advance the zoom lens optical system 7 to a desired preset position. Then, while the memory switch is on, the position of the zoom lens optical system 7 (the actual position detected via the position signal detection section 16) at the time when the position preset zoom switch 20 is switched from OFF to ON is stored in the CPU 6 as a preset position.
Next, the memory setting procedure of the preset speed will be explained.
When the preset speed is stored in memory, the actual drive speed required for the zoom lens optical system 7 can be detected by inputting the output from the speed detection section 13 into the CPU 6 via the speed signal calculation section 14 and the A/D converter 15.
Furthermore, whether the zoom control switch 1 is operated or not, which is required for storing the preset speed, is evaluated by confirming the following sequence. That is, an instruction signal proportional to the operation amount of the zoom control switch 1 is outputted from the instruction signal generating section 2, and inputted into the CPU 6 via the zoom speed variable volume 3, the instruction signal calculation section 4, and the A/D converter 5.
In this memory setting procedure, the user operates the zoom control switch 1. While the zoom lens optical system 7 is in operation with a preset speed prepared in advance, the drive speed of the zoom lens optical system 7 (the actual drive speed of the zoom lens optical system 7 detected via the speed signal detection section 13) at the time when the memory switch 24 is switched from OFF to ON is stored in the CPU 6 as a preset speed.
Next, the memory setting procedure of the preset speed and preset direction will be explained.
In this memory setting procedure, the user operates the zoom control switch 1. While the zoom lens optical system 7 is in operation with a preset speed prepared in advance and in a preset direction prepared in advance, the drive speed and direction of the zoom lens optical system 7 (actual drive speed and actual drive direction of the zoom lens optical system 7 detected via the A/D converter 15) at the time when the memory switch is switched from OFF to ON are stored in the CPU 6 as a preset speed and a preset direction.
Next, the operation method of each preset drive will be explained.
At first, the operation method of “position preset zoom control” will be explained.
For an actual use of the preset function, the preset drive will be explained.
When the position preset zoom switch 20 is turned on, the present position of the zoom lens optical system 7 is detected by inputting the output from the position signal detection section 16 into the CPU 6 via the position signal calculation section 17 and the A/D converter 18 and compared with a stored preset position. When this position is not consistent, in order to move the position of the zoom optical system 7 up to the stored preset position, the instruction signal from the CPU 6, which is calculated so as to drive with the preset speed, is inputted into the electric power amplifier 11 via the D/A converter 8, the instruction signal calculation section 9, and the A side of the instruction signal switching section 10, and after amplified to a predetermined level by the electric power amplifier 11, it is inputted into the motor 12. After this, the motor 12 starts driving, and the zoom lens optical system 7 also starts driving. And, when the position of the zoom lens optical system 7 coincides with the preset position, the drive stops.
Next, the operation method of “speed preset zoom control” will be explained.
When the speed preset zoom switch 22 is turned on, in order to drive the zoom lens optical system 7 in the stored preset direction with the stored speed, an instruction signal calculated by the CPU 6 is inputted into the electric power amplifier 11 via the D/A converter 8, the instruction signal calculation section 9, and the A side the instruction signal switching section 10, and then inputted into the motor 12 after amplified to a predetermined level by the electric power amplifier 11. As a result, the motor starts driving, and then the zoom lens optical system 7 also starts driving. And, the position of the zoom lens optical system 7 is moved up to the edge of drive direction, and then the drive stops.
However, in optical apparatuses having the above-mentioned preset function of the prior art, due to the preset function which uses a stored zoom lens position, the user himself or herself must perform focusing adjustment for an object at a preset position. For this reason, when the user performs image-taking of objects at different distances by using the preset function, it is necessary to perform focusing adjustment for each object at each preset position. Therefore, since focusing adjustment is necessary for different objects, there is a problem in that troublesome operations must be performed.
Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide an optical apparatus and a camera system which allow the preset image-taking without requiring focusing adjustment for objects at different distances even when a preset function is used for image-taking.